The invention relates to the connecting part of a ball joint between leg prosthesis components with a flange, intended to attach to one of the components, on which there is an adjusting element, which consists of a cup and four-sided pyramid set on its point on the center of the cup.
A corresponding embodiment can be derived from German Patent No. 19 22 619. In this case, the adjusting element composed of the cup and the pyramid is placed exactly in the middle of the attachment flange. By adjusting either of the two positional screws placed opposite each other, the ball joint can be adjusted in only two defined levels. This makes it possible, for example, to position a leg prosthesis advantageously on the load axis.
This previously known adaptor is generally used to connect the prosthetic substitute system to the prosthetic shaft for lower leg stumps and short to medium-long upper leg stumps. In the case of poor stump positioning, for example in the flexing and/or splaying direction, which can be found in particular in the constantly growing group of geriatric patients with amputated legs, in some circumstances it may be necessary in designing the prosthesis to use most of the adjustment area which is available in each direction but which is limited by its construction, so that the remaining adjustable area is no longer sufficient for adjustment according to bio-mechanical criteria.